Magnetoresistive element and magnetoresistive magnetic head, magnetic recording apparatus and magnetoresistive memory device using the same

Abstract

The present invention provides a magnetoresistive (MR) element that is excellent in MR ratio and thermal stability and includes at least one magnetic layer including a ferromagnetic material M-X expressed by M 100-a X a . Here, M is at least one selected from Fe, Co and Ni, X is expressed by X 1 b X 2 c X 3 d (X 1 is at least one selected from Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt and Au, X 2 is at least one selected from Al, Sc, Ti, V, Cr, Mn, Ga, Ge, Y, Zr, Nb, Mo, Hf, Ta, W, Re, Zn and lanthanide series elements, and X 3 is at least one selected from Si, B, C, N, O, P and S), and a, b, c and d satisfy 0.05≦a≦60, 0≦b≦60, 0≦c≦30, 0≦d≦20, and a=b+c+d.

1. A magnetoresistive memory device, comprising:
 a multi-layer film comprising at least two magnetic layers and at least one non-magnetic layer made of an insulating material interposed between the two magnetic layers, 
 wherein a resistance value changes with a relative angle formed by magnetization directions of the at least two magnetic layers, and 
 at least one of the magnetic layers is a laminated layer including a first layer of the ferromagnetic material consisting of M 100-a X a , a metal layer, and a second layer of the ferromagnetic material consisting of M 100-a X a , which are stacked in this order, 
 where M is at least one element selected from the group consisting of Fe, Co and Ni, X is one element selected from the group consisting of Pt, Pd and Ir, and a satisfies the following equation,
   0.05≦a≦60, and 
 
 wherein a ratio MR(T)/MR(280) is 0.8 or more, 
 where the MR(T) is defined as the MR ratio after heat treatment at a temperature of T° C. and the MR(280) is defined as the MR ratio after heat treatment at 280° C. 
 
     
     
       2. The magnetoresistive memory device according to  claim 1 , wherein a satisfies the following equation:
   5≦a≦60. 
 
     
     
       3. The magnetoresistive memory device according to  claim 1 , wherein X is Pt. 
     
     
       4. The magnetoresistive memory device according to  claim 1 , wherein X is Pd. 
     
     
       5. The magnetoresistive memory device according to  claim 1 , wherein X is Ir. 
     
     
       6. The magnetoresistive memory device according to  claim 1 , wherein X is Pt and a satisfies the following equation:
   5≦a≦60. 
 
     
     
       7. The magnetoresistive memory device according to  claim 1 , wherein X is Pd and a satisfies the following equation:
   5≦a≦60. 
 
     
     
       8. The magnetoresistive memory device according to  claim 1 , wherein X is Ir and a satisfies the following equation:
   5≦a≦60. 
 
     
     
       9. The magnetoresistive memory device according to  claim 1 , wherein the metal is Ru or Cr. 
     
     
       10. A magnetoresistive memory device, comprising:
 a multi-layer film comprising at least two magnetic layers and at least one non-magnetic layer made of an insulating material interposed between the two magnetic layers, 
 wherein a resistance value changes with a relative angle formed by magnetization directions of the at least two magnetic layers, and 
 at least one of the magnetic layers is a free magnetic layer and includes a ferromagnetic material consisting of M 100-a X a , 
 where M is at least one element selected from the group consisting of Fe, Co and Ni, X is one element selected from the group consisting of Pt, Pd and Ir, and a satisfies the following equation,
   0.05≦a≦60, and 
 
 wherein a ratio MR(T)/MR(280) is 0.8 or more, 
 where the MR(T) is defined as the MR ratio after heat treatment at a temperature of T° C. and the MR(280) is defined as the MR ratio after heat treatment at 280° C. 
 
     
     
       11. A The magnetoresistive memory device, comprising:
 a multi-layer film comprising at least two magnetic layers and at least one non-magnetic layer made of an insulating material interposed between the two magnetic layers, 
 wherein a resistance value changes with a relative angle formed by magnetization directions of the at least two magnetic layers, and 
 all of the magnetic layers include the ferromagnetic material consisting of M 100-a X a    
 where M is at least one element selected from the group consisting of Fe, Co and Ni, X is one element selected from the group consisting of Pt, Pd and Ir, and a satisfies the following equation,
   0.05≦a≦60, and 
 
 wherein a ratio MR(T)/MR(280) is 0.8 or more, 
 where the MR(T) is defined as the MR ratio after heat treatment at a temperature of T° C., and the MR(280) is defined as the MR ratio after heat treatment at 280° C.